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AcoustatAnswerMan 25th January 2013 06:35 PM

Vacuum tube for HO scale building
I'm a model railroader in HO scale, with a layout set in the 1950's, and one of the storefronts on my layout is 'Strickland's Radio & TV', which honors an old collegue of mine, James Strickland of Acoustat fame. As an advertisement on the front of the store, I want to hang a small vacuum tube with the heater lit.

Can anyone recommend a commonly available (and cheap) vacuum tube that would be no more than 1" to 1-1/2" tall, and fairly skinny? I'm thinking one with wire leads, as opposed to pins, might be easier to use. Of course, of primary importance is that the filament would be visible when lit.

I've considered making my own tube 'mock-up', but would really like the little 'tit' on the top of the tube, and I'm at a loss how to fake that without taking up glass blowing.

DUG 25th January 2013 07:13 PM

What about a vacuum tube with a red LED shining up through the bottom?

AcoustatAnswerMan 25th January 2013 07:23 PM

Not a bad idea, especially considering that the heat from a hot tube may give problems to the plastic building. But I still need a tube that's small enough so that it looks right for an HO-scale advertisement.

I was looking at the 6N16, which appears to be both plentiful and cheap. Does anyone have the approx physical dimensions of this tube, and is the filament visible when lit?

Enzo 25th January 2013 10:12 PM

As a model railroader myself, I appreciate your project. And as I am in show business, I know that the impression is far more important than the reality. That goes for model trains as well.

I am assuming you don't want a scale size tube, that would be smaller than the hands of your figures walking along the sidewalk.

So I guess you mean some real tube you can use as if it were a large sign.

Some thoughts. In the 1950s octal was still most common and even the old 4 and 5 pin tubes. In my thinking, the folks of that era thought of tubes as the big coke bottle things. I'd envision a flat piece of something cut to the shape of an octal coke bottle tube. If you want a tip, many of them had plate caps or grid caps atop the tubes. Such a silhouette could be cut from plexiglass and shaped with a Dremel or hand files, in fact two thin pieces could even sandwich some innards.

And if you don't like flat, and want something three dimensional, you could get a piece of lucite/plexi rod of the desired diameter, and carve that to shape. it comes in clear as well as opaque

As to a real glowing heater, I think that creates more problems than it is worth. A tiny bulb could be put into a sign, but I think I would mount the light source elsewhere and run a piece of optical fiber up to the sign. Also, if you work in plexiglass, edgelighting offers a lot of possibilities. A grain of wheat could be stuck inside the building, possibly even providing interior lighting as a bonus, and stick a hunk of fiber next to it to pipe some light out to the sign.

But even if you don;t like my octal idea, a 12AX7 type tube with the tit on top could be easily carved from plexi as well.

DO you know the Miller Engineering stuff?

They make some cool illuminated signs, but at the end of the listing there are a couple kits for making your own, with moving light patterns and stuff. Worth a look, it might suggest something for making a tube. Look under experimenter kits there. And that light up "wire" is pretty cool too. (kit 2503)

If you want an actual tube to be a HO scale sign, but also care that it be real as an inside joke, then go for it. But the average soul - my mom and dad - had only a vague idea what a tube looked like. The heater in a real tube usually just pokes out the top and bottom a little. It might LOOK more convincing if the "heater" was more or less completely visible - maybe a glowing sort of tiny spring-like thing aglow. Like an old time light bulb filament on a dimmer. If that makes sense. And just for drama, I might make it slowly pulse brighter and dimmer.

Just my own opinions. Whatever you do, it sounds like a cool project.

AcoustatAnswerMan 25th January 2013 10:35 PM

Enzo - Thanks for your well considered reply. Yes, I know Miller Engineering, as my layout features one of their animated signs. They even have a 'Rylie's Radio' that has a PERFECT animated vacuum tube, except it says Rylie's on it, darn it.

Using a real tube would tickle my fancy the most, and I have since found dimensions for the 6N16 and it's about the right size. I even found a photo of it in operation, and it looks like the filament is quite visible.

Nevertheless, your ideas of making a 'flat' tube are intriging, and it would allow me to really make it look like a 50's-era tube, especially if it had a plate cap. Hmmm...

Bibliophile 25th January 2013 10:52 PM

How about JAN 6418?
1.2 by 0.28 inches, wire leads.
Link to info: CK 6418, Tube CK6418; Röhre CK 6418 ID29670, Vacuum Pentode
These are still available and cheap.

grommeteer 26th January 2013 11:47 AM

When I was younger
2 Attachment(s)
I had an HO railway.
Here are two pictures of an EC1000, it is an SQ triode to be used in active probes, so quite small. To get an idea of its size (diam. 9.6mm, length of glass 35mm) I put in front of the last engine that remaines from my railway, a German E41.
If you take care for the transport you can have that tube. Rare. nos ,and SQ or not, there is not a lot I can do with it.

bear 27th January 2013 12:43 AM

You could get approximately the same look at the above *real tube* which would be better used as a *real tube* (imo) by taking an NE-2 neon bulb and modifying the envelope to make to look more like a tube.

Alternately, one could get some glass pipettes/tubing and do a little creative glass blowing with some creative internal parts construction and you'd have the look... an amber LED would light it about right... acrylic can be used to make a realistic looking filament...

rif 27th January 2013 12:57 AM

How about a small Christmas tree light?

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